Pump



G. C. GRAHAM April 11, 1950 PUMP 4 Sheets-Sheet 1 Filed May 28, 1946 ww90 vs m6 xw HMHHHHMMMMHII Q. i ////z. mm R w m 9% m w Q w mm w n: \f E Qi w M INVENTOR 650%: C .Gmmm M m ATTORNEY April 11, 1950 G. C. GRAHAMPUMP Filed May 28, 1946 lhlllL 4 Sheets-Sheet 2 I LJ INVENTOR 65am:(.Gmnen ATTORNEY April 1950 G. c. GRAHAM 2,503,257

PUMP

Filed May 28, 1946 4 Sheets-Sheet s INVENTOR GEORGE C 620mm ATTORNEY G.c. GRAHAM April ll, 1950 4 Sheets-Sheet 4 Filed May 28, 1946INI'EN'I'OR. 62020: C. 620mm Patented Apr. 11, 1950 UNITED STATES PATENTOFFICE PUMP George 0. Graham, Ridgewood, N. 1.

Application May 28, 1948, Serial No. 672,888

22 Claims. 1

The present invention relates to pumps or the like, and particularly todevices of this character operating on the reciprocating pistonprinciple.

An object of the invention is to provide a novel structure of the aboveindicated character which obtains the piston action or effect bymovement of the cylinders relative to the pistons.

Another object of this invention is to provide a reciprocating type ofpump which delivers a substantially constant flow of liquid from itsoutlet.

Another object of this invention is to provide a novel pump of thevariable volume type.

Another object of the invention is to provide a simple control oradjustment of the cylinder strokes relative to the pistons whereby thedevice, while operating, may deliver any amount of fluid from zero to amaximum.

Another object of the invention is to provide a device having novelmechanical movement, which is adapted for a pump, as in the exampleshown, and which also may be employed in a compressor, a gas engine, asteam engine, an air motor, a hydraulic motor, and in otherapplications.

Another object of the invention is to provide a device of the aboveindicated character which shall be simple and durable in construction,economical to manufacture,v and effective in its operation.

With such objects in view, as well as other advantages which may beincident to a utilization of the improvements, the invention comprisesthe parts and combinations thereof hereinafter set forth in thedrawings, specification and claims, with the understanding that theseveral necessary elements constituting the same may be varied inproportion, arrangement and texture without departing from the natureand scope of the invention.

To make the invention more readily understood, means are shown in theaccompanying drawings for carrying the same into practical efiect,without limiting the improvements in the useful applications thereof tothe particular constructions which, for purposes of explanation, aremade the subject of illustration.

In the drawings:

Fig. 1 is a transverse sectional view of one embodiment of theinvention, taken substantially along the lines ll of Fig.2;

Fig. 2 is a view, partially in longitudinal section and partially inside elevation, taken substantially along the line 2-2 of Fig. 1;

Fig. 2A is a diagrammatic view, in perspective, of the pump illustratingparticularly the inlet channels;

Figs. 3 and 4 are inner face views of end casing heads, taken on thelines 3-3 and 4--4, respectively, of Fig. 2;

Figs. 5 and 6 are views taken on the lines 2 55 and 8-3 respectively, ofFig. 2, showing cover plates on a rotor forming part of the structure;

Fig. 7 is a diagrammatic exploded perspective of the parts of thedevice, omitting the main housing body, but illustrating the fluidcircuit;

Figs. 8 and 9 are views similar to Figs. 1 and 2, respectively, of theinvention in modified form:

Figs. 10 and 11 are enlarged details respectively in plan and section ofthe valves of Figs.

8 and 9.

Briefly, the device comprises a revolving cylinder block having thecylinders disposed in cruciform fashion. The double-ended pistons aremounted on separate shafts one of which is adjustable to offset oneshaft with respect to the other, and the amount of the eccentricitydetermines the orbit of the cylinder block and the reciprocation of thecylinders. That is to say, the axis of the cylinder block travels in anorbit the size of which determines the relative eccentric movement ofthe cylinder block to the pistons and, therefore, the volume of deliveryper stroke. As all four cylinders discharge successively into the pumpcasing, a substantially steady flow is produced. The eccentricity of theshafts can be fixed, in which event the pump will be a constant volumepump, or suitable means may be provided for selectively adjusting theposition of the shafts from being co-axial to a predetermined maximumeccentricity thus converting the pump to the variable volume type.Porting to and from the cylinders is arranged in the end plates of thepump housing.

Referring first to the structure shown in Figs. 1 to 7 inclusive, thepump comprises a cylindrical housing 20 closed by end cover plates 22and 24, thus forming achamber 26'. An inlet connection 28 communicatesby means of manifolds external to the casing, indicated at 30 and 3! inFigs. 2 and 2A, with somewhat crescent-shaped inlet depression 32 (Figs.3 and '7) in the inner face of the end plate 22 and crescent-shapedinlet depression 33 in end plate 24. The face of end plate 22 also isprovided with a crescent-shaped outlet depression 34 having an enlargedarea 35 extending from one side thereof and the face oi. end plate 24also is provided with a crescentshaped outlet 36 having an enlarged area31, the enlarged areas being of a size and disposition as to be at alltimes in communication with the chamber 26 of the housing, ashereinafter more fully explained. A main outlet 38 leads from thechamber 26.

The cylinder block 39 in this form of the invention, is a simple rotorhaving plane end surfaces liiat right angles to the rotor axis, and acruciform axial opening 42 entirely therethrough forming a pair ofoppositely disposed cylinder portions 44 and a second pair of oppositelydisposed cylinder portions CI. The cylinder portions are of rectangularor polygonal cross sectional area. The cross section, in this case, isrectangular for facility of milling straight through the rotor.

A piston element 40. of substantially U-shape, has a cross piece ll,fixed to a drive shaft II, and inwardly extending legs 52 formingpiston-head elements operating in the cylinders ll. The shaft ll isiournaled in a bearing portion II of the cover plate 2| and having astuiling box construction It therein. It will be noted that the axis ofthe shaft does not coincide with the axis of chamber 2|.

A second piston element II, also of substantially U-shape. has a crosspiece II. which is rotatably mounted on a shaft or trunnion It. throughthe intermediary of a bearing sleeve l9. and has inwardly extending legsI forming piston head elements operating in cylinders ll.

One side of the cylinder portions 44 are closed by a thin shield or disc82, secured to one end face of the rotor 39, and having a diametralrectangular through opening it in register with the cylinder portionsll. Another thin shield or disc 06 is secured to the opposite face ofthe rotor so as to close one side of cylinder portions 45, and having asimilar opening It in register with cylinder portions It.

When assembled, the piston element 48 fits in the cylinder block 1! sothat the piston elements I! are in the cylinder portions 45 with theouter .end of the cross piece 48 extending into the slot 84 of the discI, and the piston element 54 is assembled in the opposite side of thecylinder block so that the piston elements II are in the cylinderportions 44 and the outer end of the cross piece It extends into theslot I in the cover disc 6!. with this arrangement the cylinder block isfreely mounted so as to reciprocate with respect to the piston elements,as will be described.

The slots 84 and ll are of a size to register with the crescent-shapedportions of the inlet and outlet depressions 32 to l in the end plates22 and 24 as the cylinder block 39 revolves in the main housing and, aswill be apparent, as one of the cylinders 45 is discharging into theoutlet 38 of end plate 24, the opposite cylinder 45 is on the suctionstroke, being in communication with the inlet 33. Similarly, thecylinders 44 are on the compression and suction strokes in communicationwith the depressions ,3! and N of end plate 22, but these actions takeplace 90 out of phase with the corresponding actions of the cylinders45. The only times when the slots '4 and I are not in communication withthe depressions I! to 36 of the respective end plates is when therespective slots are in the vertical position (of Figs. 1-7), in whichposition the crescent-shaped depressions are spaced apart slightly morethan the width of the piston elements. The derivation of thecrescent-shaped depressions 32 to SI and their locations on the endplates will be explained hereinafter.

It will be noted, that during the assembly of the apparatus, the pistonelements it and 4, are moved toward each other, from the positions ofPig. '1. into the cruciform opening of the rotor ll until the crosspieces it and 56 are close to each other, separated as by a distance A,Fig. 2, and the piston heads I! of the element It axially overlap thepiston heads it of the element II, and vice versa.

It has been explained that piston element 4.

is fast on drive shaft II and that piston element It is mounted on atrunnion ll. Referring to Fig. 2. the trunnion ll is adiustably mountedthrough the intermediary of a flange II on the inner end of a shaft 12which is rotatably mounted in a bearing sleeve 18 in the cover plate 22.Shaft 12 has a peripheral slot I1, and the hattened end of a screw ll,fixed in sleeve It, engages in said slot. In the position shown in Fig.2 the shafts I and II have their maximum eccentricity, and the screw isat one end of slot 11. when shaft 12 is turned, by any suitable means,the axes of shafts II and SI are aligned at an intermediate position ofthe pin in the slot. The apparatus may be so arranged by enlarging thecasing Ill and extending slot 11 past the zero position at the presentend of the slot that the whole pump action will be reversed, as will beunderstood. Any suitable means may be provided for clamping the shaft 12in the selected position. In the showing of Fig. 2 this is combined withan automatic regulator of the reaction type, the mechanism of which willbe described. and subsequently, its mode of operation.

A cap ll, screw threaded in a sleeve 22 of the cover plate 22, has ahandle 84, and is fixed in its adjusted positions by means of lock nutI. One end of a coiled spring It is secured to the cap ll, as by a screwll, and the other end is secured to the shaft 12 as by a screw it. Abalance between the pressure of the liquid and the pressure exerted bythe spring it determines the eccentricity of the shafts SI and II.

As shown in Fig. 2, and as seen from a comparison of Figs. 3 and 4, thedrive shaft 53, the

runnion 5i and the shaft 12, are each eccentric to the others, and whenthe trunnion 58 is in its position of maximum eccentricity relative tothe drive shaft 50, which is the position of maximum pumping capacity ofthe device, the axes of the trunnion SI and shaft 50 are not in the samevertical plane. Furthermore, none of the axes need to or do coincidewith the axis of chamber 28.

As a result of the eccentric mounting of the trlmnion 58 and shaft 50,the cylinder block 3!, is caused to both rotate and revolve in an orbitto produce pumping strokes between the pistons and cylinders. That is tosay, with the parts assembled as described, as the drive shaft 5| isrotated the piston element 6 rotates with the shaft, and if we ignorefor the moment the presence of the other piston element 54 it is clearthat the cylinder block 39 will merely rotate about the axis of theshaft 50, and there will be no relative displacement of piston andcylinder block and hence no pumping action. Likewise, if the axes ofshaft 50 and trunnion 50 are aligned, all parts will rotate on a commonaxis and still there will be no pumping action. As soon as the trunnion58 is displaced from axial alignment with the shaft It. the rotativeefiort of the cylinder block tends to divide between the displaced axesand to rotate the cylinder block about a new axis. Since this is notpossible physically, the turning force exerted by the displaced pistonelement 54 is converted into lateral motion which physically moves thecylinder block 39 transversely of its axis with the piston element 48acting as a guide.

Starting from a position in which piston element I6 is in mid-positionin the cylinders 45 and the piston element is in its uppermost positionin Fig. 7. upon a rotation of the cylinder block the relativeeccentricity of the piston elements it and It with respect to thecylinder block has altered so that the center of rotation of thecylinder block more nearly coincides with the axis of the trunnion 58,and the cylinder block has completed its movement to the right wherepiston element 46 is at one limit of its stroke and piston element 54 isin its mid-position. In the course of the next 90 of rotation, the axisor rotation of the cylinder block approaches that of the shaft 56, butnow the cylinder block has moved toward the left so that piston element46 is in its mid position and piston element 54 is at the opposite orlower limits of its stroke. With the third 90 rotation the cylinderblock has moved so piston element 46 has reached the opposite limit ofits stroke and upon the final 90 rotation the parts have returned to thestarting position. As the rotation of the cylinder block is continuous,the resultant of these forces is to cause the axis of the cylinder blockto describe a complete orbit while the piston elements rotate aboutfixed axes. Thus, a reciprocatory movement occurs between the cylinderblock and the piston elements which reverses as to each piston elementin each half revolution of the cylinder block, and by reason of thepiston elements being displaced 90 with respect to each other, thepumping strokes successively reach their maximum limits 90 out of Phase.

As the cylinder block rotates each c linder 44 and successivelyregisters with its associated inlet and outlet depressions 32 to 36,through the slots 68 and 64 respectively, such registrations being timedwith the suction and compression strokes respectively. Thus, While oneof the cylinders 44 is on its suction stroke (and in register throughslot 68 with inlet 32 of'end plate 22) the opposite cylinder 44 is onits compression stroke (and in register through slot 68 with outlet 34of end plate 22). Likewise,. 90 out of phase with the foregoingoperations, while one of the cylinders 45 is on its suction stroke (andin register through slots 64 with inlet 33 of end plate 24) the oppositecylinder 45 is on its compression stroke (and in register through slot64 with outlet 36 of end plate 24).

The so-called crescent-shape of the depressions 32 to 36 is derived bycoincidence with the paths of the rotating pistons and cylinders, theterminus B (Figs. 3 and 4) of each coinciding with the locations of thepistons at the start of their respective suction and compressionstrokes, and the terminus C coinciding with the locations of the pistonsat the finish of those strokes. The de pressions widen from points Btoward their centers and then reduce in width toward points C with theopening and closing of the cylinders respectively, the'size, locationand shapes of the depressions being chosen to provide maximum pumpefliciency and capacity.

It will be noted that the depressions 32 and 34 in end plate 22 areconsiderably wider than the corresponding inlet and outlet depressions33 and 36 in end plate 24, the reason being that when the controlmechanism is adjusted to offset the drive shaft and trunnion 58, thereis a, corresponding displacement of the cylinder block or of pistons 52,as will be described, which displacement alters the orbits of thepistons, proportional to the amount of the lateral displacement.

The outlet depressions 34 and 36 are provided respectively with centralenlargements 35 and 31, extending substantially to the edge of thechamber 26, because the crescent-shaped portions of the outletdepressions are within the orbit of the cylinder block and hence coveredby the discs 62 and 66. The enlargements 36 extend outside the orbit ofthe cylinder block so that the fluid discharged from the cylinders 44and 45 enters the chamber 26, from which it passes through the outlet38. It should be noted that the orbit of the cylinder block does nottouch the cylindrical casing at any point in the construction thus fardescribed.

As stated above, this device has the greatest pumping capacity when thetrunnion 58 has the position of Figs. 1 and 2 relative to the driveshaft 50. To vary the pump capacity, or in other words, to shorten thecylinder strokes, it is only necessary to turn the handle 84, which willgradually diminish the eccentricity of the trunnion 58 to the driveshaft 50 from the position of maximum eccentricity shown, to a positionof zero eccentricity wherein the axes of the trunnion and the driveshaft are concentric or in line. In the latter position, there is nopiston action, but only idle rotation of all the rotatable parts. If thehandle 84 is placed in any position in which the screw I8 isintermediate the ends of slot I1, the degree of eccentricity and thepump capacity will be in accordance with-the handle position. I

It will be understood that rotation of shaft I2 to offset the axes ofshaft 50 and trunnion 58 actually displaces the piston so as to bringone set of the pistons 52 or 60 at the limit or near the limit of thepumping strokes. By doing this, an eccentricity is introduced in therelationship of the cylinders, and one or two of the cylinders is incommunication with one or both of the outlet depressions 34 and 36.Since the. cylinder block is entirely free, the back pressure on thepiston elements 46 and 54 is in the opposite direction to the forceexerted by the coil spring 86. If the pressure of the coil spring isovercome by the back pressure of the fluid system, the cylinder block ismoved automatically in a direction to reduce the eccentricrelationships; and oppositely, so long as the back pressure is less thanthe force exerted by spring 36, the eccentric relationships will bemaintained in the maximum position to which they had been adjusted.

, Referring to the form shown in Figs. 8 to 11, wher the same principlesare applied as hereinbefore described, the pump comprises a cylindricalcasing I20 closed by end plates I22 and I24, forming a chamber I26. andprovided with an outlet connection I28. The cylinder block in thisinstance ,i'comprises four cylinders joined in cruciform shape withcylinders I30 and I32 disposed oppositely to each other and cylindersI34 and I36 disposed oppositely to each other and displaced with respectto the cylinders I30 and I32. The cylinders are joined together at theirlower ends to form a central chamber I38, and eizh of the cylinders isclosed by a suitable head A drive shaft I42 is rotatably mounted in asleeve bearing I44 on end plate I22. and in which is a suitable packinggland-I46.- The shaft I42 extends into the cylinder block and at itsinner end has secured thereto a cross piece I48 on the opposite ends ofwhich are piston heads I50 and I 52 respectively fitting in andcooperating with the cylinders I34 and I36. A stub shaft I56 is mountedin end plate I24, with its inner end projecting into the chamber I38 ofthe cylinder block and forming a trunnion for a cross piece I58, whichhas on its opposite ends piston heads I60 and I62 respectively operatingin cylinders I30 and I32.

Each of the piston heads I66, I62, I66 and I62 is provided with anopening I64 which establishes communication between the central chamberI66 of the cylinder block and the respective cylinders I64. I66, I66 andI62. Each of the openings I64 is closed by a feather or other type valvemechanism indicated at I65, and adapted to open to permit flow from thechamber I36 into each of the cylinders and to close automatically,either under spring action or by back pressure, to prevent flow in theopposite direction. Likewise, each of the cylinder heads I40 has a portI66, which also may be closed by a feather or other type of valvemechanism, indicated at I61, and adapted to establish communication fromthe interior of the respective cylinders to the chamber I26, butpreventing fiow in the opposite direction.

The valve mechanisms I66 and I61 may be alike in construction and oneform thereof is shown in detail in Figs. 10 and 11. The valve body is inthe form of a plug fitting the respective ports and openings, and is.provided with a plurality of apertures I66 which are covered by a thinflexible plate I66 fastened at its center to the valve body.

It will be noted that the cylinder block is freely suspended in thecasing I26, as well as on the piston lements. One set of the pistonelements is fast upon the drive shaft I42 and the other set is pivotallymounted on the trunnion I66. When the axis of the trunnion is offsetfrom the axis of the drive shaft I42 so that, in the position shown inthe drawings, piston heads I60 and I62 are respectively at the limits oftheir compression and suction strokes while piston heads I66 and I62 aremidway in their respective cylinders, rotation of the drive shaftrotates the pistons and causes the cylinder block to describe a completeorbit the result of which is to move the cylinders with respect to thepiston heads to successfully expand and-contract the cylinder spaces toproduce suction and compression pumping strokes.

The chamber I26 is provided with an inlet connection I12 which opensinto the chamber I26 through the inlet opening I14 in end plat I24,which inlet opening surrounds the trunnion I56 and is opposite the openchamber I66 of the cylinder block. The space between the cylinder blockand the end plate I24 is closed by any suitable means, such as theSylphon bellows washer I16, which is secured to the cylinder block so asto close its central chamber I36 n the side adjacent the end plate I24.On the opposite Sylphon bellows type of washer I16 which surrounds theopening into the chamber I66 and fills the space between the cylinderblock and the end plate I22. The Sylphon washers I16 and I1! form anauxiliary closed chamber I66 within the chamber I26, and being attachedto the cylinder block so as to move therewith. Accordin ly, they must beof a size to allow for the orbital movement of the cylinder block sothat this chamber I" is never out of communication with the inletopening I14.

The chamber I16 of the cylinder block is at all times in opencommunication with the auxiliary chamber I60 so that there is fluidbehind each of the cylinder heads. As the cylinder block is moved toexpand the space of one of the cylinders, a suction stroke, the valveI66 thereof opens to admit fluid from the chamber I66 into theparticular cylinder. At the end of the suction side the cylinder blockalso is provided with a 8 stroke the compression stroke begins whereuponthe valve I66 closes and the valve I16 in the cylinder head opens sothat fluid is forced out of the cylinder into the chamber I26, fromwhich it fiows through the outlet opening I26.

Other modifications may be made in the arrangement and location of partswithin the spirit and scope of my invention.

I claim:

1. In a hydraulic device, the combination of means including a rotatablemember forming a plurality of cylinders, a shaft supporting one or morepistons for a corresponding number of said cylinders, a drive shafteccentric to said first shaft carrying one or more pistons for acorresponding number of other of said cylinders and operative to drivethe piston or pistons on said first shaft through the intermediary ofsaid rotatable member and to drive the latter through the intermediaryof the drive shaft pistons whereby to alternately expand and contractthe cylinder spaces in the performance of useful work, and inlet andoutlet connections to said cylinders.

2. In a hydraulic device. the combination of means including a rotatablemember forming a plurality of cylinders, a shaft supporting one or morepistons for a corresponding number of said cylinders, a drive shafteccentric to said first shaft carrying one or more pistons for acorresponding number of other of said cylinders and operative to drivethe piston or pistons oi said first shaft through the intermediary ofsaid rotatable member and to drive the latter through the intermediaryof the drive shaft pistons to provide the piston effect by movement ofthe cylinders relative to the pistons. means for varying the degree ofeccentricity between said shafts. and inlet and outlet connections tosaid cylinders.

3. In a hydraulic device, the combination of means including a rotatablemember forming a plurality of pairs of radially opposite cylinders, ashaft supporting at least one pair of opposed pistons for acorresponding pair of said cylinders, a drive shaft eccentric to saidfirst shaft carrying at least one pair of opposed pistons for anotherpair of said cylinders and operative to drive the pistons of said firstshaft through the intermediary of said rotatable member and to drive thelatter through the intermediary of the drive shaft pistons whereby thespaces of opposed cylinders are oppositely and alternately contracted bymovement of the cylinders relative to the pistons, and inlet and outletconnections to said cylinders.

4. In a hydraulic device, the combination of means including a rotatablemember forming a plurality of pairs of radially opposite cylinders, ashaft supporting at least one pair of opposed pistons for acorresponding pair of said cylinders, a drive shaft eccentric to saidfirst shaft carrying at least one pair of opposed pistons for anotherpair of said cylinders and operative to drive the pistons of said firstshaft through the intermediary of said rotatable member and to drive thelatter through the intermediary of the drive shaft pistons whereby thepiston effect is obtained by movement of the cylinders relative to thepistons, means for varying the degree of eccentricity between saidshafts, and inlet and outlet connections to said cylinders.

5. In a hydraulic device, the combination of means including a rotatablemember forming a plurality of cylinders of polygonal cross sectionalcontour. a shaft supporting one or more piston elements of correspondingcontour for a corresponding number of said cylinders, a drive shafteccentric to said first shaft carrying one or more pistons ofcorresponding contour for a corresponding number of other of saidcylinders and operative to drive the piston or pistons of said firstshaft through the intermediary of said rotatable member and to drive thelatter through the intermediary of the drive shaft pistons to providethe piston effect by movement of the cylinders relative to the pistons,and inlet and outlet connections to said cylinders.

6. In a hydraulic device, the combination of a housing forming a chamberhaving parallel inner end surfaces, means including-a rotatable memberin said chamber having arallel ends and a substantially cruciformopening axially therethrough cooperating with said inner end chambersurfaces to form a piston cylinder of each leg of said cruciform openingand of rectangular cross section, a shaft parallel to said openingsupporting an element of substantially U-shape, the legs of whichU-shaped element form pistons in diametrically opposed relation in saidcylinders, a drive shaft eccentric to said first shaft also carrying anelement of substantially U- shape, the legs of which form' pistons inthe remaining of said cylinders, said drive shaft operating to drive thepistons of said first shaft through the intermediary of the drive shaftpistons whereby the piston effect is pwvided by movement of thecylinders relative to the pistons, and inlet and outlet connections tosaid cylinders.

7. In a hydraulic device, the combination of a housing forming a chamberhaving axially opposite bearing portions eccentric relative to eachother, shafts including a driving shaft and a second shaft journaled insaid bearings, respectively, a member rotatable in said chamber, saidmember also revolving about an axis substantially parallel to the axesof said bearing'portions and having a plurality of pairs of cylinders,the cylinders of each pair being spaced substantially radially from eachother at opposite sides of the axis of said rotatable member and havingaxes disposed at an angle to the axes of the other cylinder pairs,pistons in the cylinders of certain of said pairs and carried by saiddriving shaft, pistons in the cylinders of the other cy linder pairsmounted for rotation about the axis of the second shaft, the arrangementoperating said rotatable member by the driving shaft through theintermediary of said pistons whereby the rotatable member causes thepiston efiect by movement of the cylinders relative to the pistons, andinlet and outlet connections to said cylinders.

8. In a hydraulic device, a cylindrical casing, end plates closing saidcasing, the inner faces of the end plates being provided with spacedapart substantially crescent-shaped inlet and outlet depressions, inletopenings into said inlet depressions, a connection from the outletdepressions to the interior of said casing, a main outlet from saidcasing, a rotatable and revolvin cylinder block in said casing andhaving pairs of opposed cylinders, a drive shaft mounted in one, of saidend plates, a piston element secured to said drive shaft and havingopposed piston heads operating in one pair of said cylinders, a trunnionmounted in the opposite end plate of the casing, a piston elementrotatable thereon and having opposed piston heads operating in anotherpair of said cylinders, the axes of the shaft and trunnion beingeccentric with respect to each other, and ported discs in the spacebetween the sides of said cylinder block and the end plates and arranged10 to successively port said cylinders to the inlet and outletdepressions, respectively.

9. In a hydraulic device, a cylindrical casing, end plates closing saidcasing, the inner faces of the end plates being provided withsubstantially crescent-shaped inlet and outlet depressions, an inletopening into said inlet depression, a connection from the outletdepression to the interior of said casing, a main outlet from saidcasing, a rotatable and revolving cylinder block in said casing andhaving pairs of opposed cylinders, a drive shaft mounted in one of saidend plates, a piston element secured to said drive shaft and havingopposed piston heads operating in one pair of said cylinders, a trunnionmounted in the opposite end plate of the casing, a piston elementrotatable thereon and having opposed piston heads operating in anotherpair of said cylinders, the axes of the shaft and trunnion beingeccentric with respect to each other, and ported discs closing saidcylinder block and arranged to successively port said cylinders to theinlet and outlet depressions, respectively.

10. In a hydraulic device, a cylindrical casing,

end plates closing said casing, the inner faces of v the end platesbeing provided with spaced apart inlet and outlet depressions, inletopenings into said inlet depressions, a connection from the outletdepressions to the interior of said casing, a main outlet from saidcasing, a rotatable and revolving cylinder block in said casing andhaving pairs of cylinders, a drive shaft mounted in one of said endplates, a piston element secured to said drive shaft and having pistonheads'operating in one pair of said cylinders, a trunnion mounted in theopposite end plate of the casing, a piston element rotatable thereon andhaving piston heads operating in another pair of said cylinders, theaxes of the shaft and trunnion being eccentric with respect to eachother, and ported discs closing said cylinder block and arranged tosuccessively port said cylinders to the inlet and outlet depressions,respectively.

11. In a hydraulic device, a cylindrical casing,

end plates closing said casing, inlet and outlet openings, a rotatableand revolving cylinder block in said casing and having pairs of opposedcylinders, a drive shaft mounted in one of said end plates, a pistonelement secured to said drive shaft and having opposed piston headsoperating in one pair of said cylinders, a trunnion mounted in theopposite end plate of the casing, a piston element rotatable thereon andhaving opposed piston heads operating in another pair of said cylinders,the axes of the shaft and trunnion being eccentric with respect to eachother, whereby the movements of the cylinder block successively expandand contract the spaces in said cylinders, and means for alternatelyestablishing communication between each of said cylinders and said inletand outlet openings.

12. In a. hydraulic device, a cylindrical casing, end plates closingsaid casing, inlet and outlet openings, a rotatable and revolvingcylinder block in said casing and having pairs of opposed cylinders, adrive shaft mounted in one of said end plates; a piston element securedto said drive shaft and having opposed piston heads operating in onepair of said cylinders, a trunnion mounted in the opposite end plate ofthe casing, a piston element rotatable thereon and having opposed pistonheads operating in another pair of said cylinders, the axes of the shaftand trumiion being eccentric with respect to each other, whereby themovements of the cylinder block succes- 1 l sively expand and contractthe spaces in said cylinder, and ported discs located on each side ofsaid cylinder block and arranged to successively port said cylinders tothe inlet and outlet openings.

13. In a hydraulic device, a cylindrical casing, end plates closing saidcasing, inlet and outlet openings, a rotatable and revolving cylinderblock in said casing and having pairs of opposed cylinders, a driveshaft mounted in one of said end plates. a piston element secured tosaid drive shaft and having opposed piston heads operating in one pairof said cylinders, a trunnion mounted in the opposite end plate of thecasing, a piston element rotatable thereon and having opposed pistonheads operating in another pair of said cylinders, the axes of the shaftand trunnion being eccentric with respect to each other, whereby themovements of the cylinder block successiveLy expand and contract thespaces in said cylinders, means for alternately establishingcommunication between each of said cylinders and said inlet and outletopenings, an adjustable mounting for the trunnion comprising a rotatablemember, means for rotating said member to alter the eccentricity betweenthe driving shaft and trunnion, and means for locking the adjustingmeans in the adjusted position.

14. In a hydraulic device, a cylindrical casing. end plates closing saidcasing, the inner faces of the end plates being provided with spacedapart substantially crescent-shaped inlet and outlet depressions, inletopenings into said inlet depressions, a connection from the outletdepressions to the interior of said casing, a main outlet from saidcasing, a rotatable and revolving cylinder block in said casing andhaving pairs of opposed cylinders, a drive shaft mounted in one of saidend plates, a piston element secured to said drive shaft and havingopposed piston heads operating in one pair of said cylinders, a trunnionmounted in the opposite end plate of the casing, a piston elementrotatable thereon and having opposed piston heads operating in anotherpair of said cylinders. the axes of the shaft and trunnion beingeccentric with respect to each other, an adjustable mounting for thetrunnion comprising a rotatable member, means for rotating said memberto alter the eccentricity between the driving shaft and trunnion, meansfor locking the adjusting means in the adjusted position, and porteddiscs in the space between the sides of said cylinder block and the endplates and arranged to successively port said cylinders to the inlet andoutlet depressions, respectively.

15. In a hydraulic device, a cylindrical casing, end plates closing saidcasing, inlet and outlet openings, a rotatable and revolving cylinderblock in said casing and having pairs of opposed cylinders, a driveshaft mounted in one of said end plates, a piston element secured tosaid drive shaft and having opposed piston heads operating in one ofsaid pairs of cylinders, a second shaft rotatably mounted in theopposite end plate of the casing, a trimnion mounted on the second shaftand movable from a position in which the axes of the driving shaft andtrunnion are aligned to selected positions in which the axes of thedriving shaft and trunnion are eccentric with rupect to each other, apiston element rotatable on the trunnion and having opposed piston headsoperating in another pair of said cylinders, the eccentric adjustment ofthe trunnion also eifecting an eccentric relationship between therespective piston elements. means for adjusting the 12 second shaft, aspring connected between said shaft and said adjusting means, means forlooking the adjusting means in adjusted positions, and means foralternately establishing communication between each of said cylindersand said inlet and outlet openings, whereby the fluid pressure isautomatically balanced against the pressure of said spring to maintainthe output of said device at a substantially constant pressure.

16. In a hydraulic device, a cylindrical casing, end plates closing saidcasing, inlet and outlet openings, a rotatable and revolving cylinderblock in said casing and having pairs of cylinders therein, a driveshaft mounted in one ofsaid end plates, a piston element secured to saiddrive shaft and having piston heads operating in one of said pairs ofcylinders, a trunnion, means for pivotally mounting the trunnion in theopposite end plate of the casing so as to be movable from a position inwhich the axes of th driving shaft and trunnion are aligned to selectedpositions in which the axes of the driving shaft and trunnion areeccentric with respect to each other, a piston element rotatable on thetrunnion and having piston heads operating in another pair of saidcylinders, the eccentric adjustment of the trunnion also effecting aneccentric relationship between the respective piston elements, means foradjusting the trunnion mounting means. pressure reactive means betweensaid mounting means and said adjusting means, and means for alternatelyestablishing communication between each of said cylinders and said inletand outlet openings whereby the fluid pressure is automatically balancedagainst the pressure of said reactive means to maintain the output ofsaid device at a substantially constant pressure.

17. In a hydraulic device, the combination of a casing, end platesclosing said casing, an outlet therefrom, a drive shaft mounted in oneof said end plates, a trunnion mounted in the other oi said end plates,the axes of the shaft and trunnion being offset from each other, a cyl-'inder block having a plurality of pairs of opposed cylinders therein anda central inlet chamher, the free ends of the shaft and trunnionextending into said chamber, a piston element secured to the free end ofsaid drive shaft and having a pair of opposed piston heads operating inone pair of said cylinders, a second piston element which is mounted onthe free end of said trunnion and has a pair of opposed piston headsoperating in another pair of said cylinders, whereby rotation of thedrive shaft and its piston element will rotate and revolve'the cylinderblock, an auxilary chamber in said casing in cor imunication with theinlet chamber of the cylinder block, an inlet opening in the easing andto said auxiliary chamber, ports in each of said piston headsestablishing communication between the inlet chamber and the space ineach of said cylinders, valve means controlling each of said ports, anoutlet port in each of said cylinders opening into said casing, andvalve means controlling the port in each of said cylinders.

18. In a hydraulic device, the combination of a casing, end platesclosing said casing, an outlet therefrom, a drive shaft mounted in oneof said end plates, a trunnion mounted in the other of said end plates,the axes of the shaft and trunnion being offset from each other, acylinder block having a plurality of pairs of cylinders therein and aninlet chamber, the free ends of the shaft and trunnion extending intosaid cylinder block, a piston element secured to the free end with theinlet chamber of the cylinder block, an

inlet opening to said auxiliary chamber, ports in each of said pistonheads establishing communication between the inlet chamber and the spacein each of said cylinders, valve means controllin each of said ports, anoutlet port in each of said cylinders opening into said casing, andvalve means controlling the port in each of said cylinders.

19. In a hydraulic device, the combination of a casing, end platesclosing said casing, an out- I let therefrom, a drive shaft mounted inone of said end plates, at trunnion mounted in the other of said endplates, the axes of the shaft and trunnion being offset from each other,a cylinder block having a plurality of pairs of cylinders therein and aninlet chamber, the free ends of the shaft and trunnion extending intosaid cylinder block, a piston element secured to the free end of saiddrive shaft and having a pair of piston heads operating in one pair ofsaid cylinders, a second piston element which is mounted on the free endof said trunnion and has a pair of piston heads operating in anotherpair of said cylinders, whereby rotation of the drive shaft and itspiston element will rotate and revolve the cylinder block, an inletopening in said casing and connected to said chamber, ports in each ofsaid piston heads establishing communication between the inlet chamberand the space in each of said cylinders, valve means controlling each ofsaid ports, an outlet port in each of said cylinders opening into saidcasing, and valve means controlling the port in each of said cylinders.

20. In a hydraulic device, an enclosing casing, inlet and outletopenings therein, a cylinder block movable in said casing and havingpairs of opposed cylinders, a drive shaft mounted in said casing, apiston element mounted on said drive shaft and having opposed pistonheads operating in one pair of said cylinders, a second shaft mounted insaid casing, a piston element connected to said second shaft and havingopposed piston heads operating in another pair of said cylinders, theaxes of said shafts being eccentric 14 with respect to each other,whereby the movements of the cylinder block successively expand andcontract the spaces in said cylinders, and means for alternatelyestablishing communication between each of said cylinders and said inletand outlet openings.

21. In a hydraulic device, a casing, inlet and outlet openings therein,a cylinder block movable in said casing and having pairs of opposedcylinders, a drive shaft mounted in said casing, a piston elementsecured to said drive shaft and having opposed piston heads operating inone pair of said cylinders, a second shaft, an adjustable mounting forsaid second shaft and arranged to adjust the relationship of said shaftsbetween a substantially coaxial relationship and a, predeterminedeccentricity of said shafts, means for maintaining the shafts in theadjusted relationship, a piston element mounted on said second shaft andhaving opposed piston heads operating in another pair of said cylinders,whereby the movements of the cylinder block successively expand andcontract the spaces in said cylinders, and means for alternatelyestablishing commumcation between each of said cylinders and said inletand outlet openings.

22. In a hydraulic device, a casing, inlet and outlet openings therein,a cylinder block movable in said casing and having pairs of opposedcylinders, a drive shaft mounted in said casing, a piston elementmounted on said drive shaft and having opposed piston heads operating inone of said pairs of cylinders, a second piston element having opposedpiston heads operating in another of said pairs of cylinders, anadjustable mounting for said second piston element to effect aneccentric relationship between the respective piston elements andincluding an adjustable pressure reactive element, and means foralternately establishing communication between each of said cylindersand said inlet and outlet openings, whereby the fluid pressure isautomatically balanced against the pressure reactive element to maintainthe output of said device at a substantially constant pressure.

' GEORGE C. GRAHAM.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 562,500 Sperry June 23, 18961,852,953 Grundy Sept. 14. 1920

